This invention relates to a substrate on which electrical parts are mounted, and more particularly, to a substrate having such a structure that electrical parts mounted thereon do not protrude from the bottom plane thereof and a mounting method for mounting electrical parts on said substrate.
Generally in a miniaturized electronic devices, chips and other electric parts with lead wires are mounted together on one substrate. Conventional methods for mounting those parts have been such that after positioning the parts with lead wires on the substrate and clinching the lead wires on the back surface of the substrate, the lead wires are soldered and secured to the wiring pattern while chips, after being temporarily fixed on the back surface of the substrate by adhesive, are soldered and secured at electrode portions thereof together with the wiring pattern. This may be performed in the manner of mounting the chips first and the parts with lead wires later or in a manner mounting the parts with lead wires first and the chips later.
However, the former manner has the drawback that chips protruding from the back surface of the substrate disturb clinching and cutting work of the parts with lead wires on the back surface and are apt to be damaged or fall down. The latter also has the drawback that, although the lead wires can easily be clinched, since the lead wires already clinched along the back surface cause uneveness thereof, it is difficult to accurately spread adhesive for temporarily fixing the chips so that the electrode portions of the chips cannot be soldered well readily.